JPH08290182A - Ozone contact tank - Google Patents

Abstract

PURPOSE: To improve treating efficiency by improving gas-liquid contact performance of an ozonized gas with water to be treated. CONSTITUTION: An ozone contact tank 1 is provided with a contact tank 1a, to which water to be treated flows in, and an ozone diffuser 4 composed of a header pipe 2 and diffusing pipe 3 is arranged in the contact tank 1a. The ozone diffuser 4 is arranged on the bottom 21 of the contact tank 1a without forming a passage in between the diffuser and the bottom 21.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an ozone contact tank for carrying out gas-liquid contact reaction with ozonized gas for performing advanced water purification treatment, advanced sewage treatment and the like.

[0002]

2. Description of the Related Art FIG. 4 is a block diagram showing a one-divided portion of a conventional ozone contact tank used for advanced water purification treatment and the like. In FIG. 4, the ozone contact tank 1 includes a contact tank 1a, and in the contact tank 1a, an ozone diffuser 4 including a header pipe 2 and a plurality of diffuser cylinders 3 is arranged. Ozone diffuser 4
Is 0.5 to 0.8 from the bottom of the contact tank 1a depending on the base 5.
It is placed so as to float about m.

The reason why the ozone diffuser 4 is floated from the bottom surface by the base 5 is considered to be as follows.
That is, the history of ozone aeration for clean water is short, and conventional aeration technology for sewage is used as it is. In the case of aerating sewage, if the ozone diffuser is directly attached to the bottom surface, it will be buried by sludge and the like, but there is no such concern in clean water, and the problem is how to absorb ozone.

In FIG. 4, an ozonized gas from an ozone generator (not shown) is supplied to the scattering cylinder 3 from the riser pipe 6 through the header pipe 2. The water to be treated which has been pretreated by coagulating sedimentation, sand filtration, etc.
Supplied by. In the contact tank 1a, the rising bubble flow of the ozonized gas generated from the scattering cylinder 3 and the water to be treated are in gas-liquid contact with each other, and the odorous component of the water to be treated, such as 2-methylisoborneol (2-MIB), is exposed. The oxide is oxidatively decomposed,
The treated water after the treatment flows out from the lower opening of the partition wall 8 of the contact tank 1a. Actually, a plurality of contact tanks 1a shown in FIG. 4 are connected in series in two to three stages via a bypass portion according to the processing target.

[0005]

In all stages of the ozone contact tank 1 having the conventional structure shown in FIG. 4, the 2-MIB removal rate is 8%.
It becomes 0 to 90%, and the ozone absorption rate becomes around 90%.
However, at present, there is almost no research or study on the structure in order to improve the treatment performance of the large ozone contact tank 1.

The inventors of the present invention measured the water flow and water quality in the ozone contact tank 1 with an experimental apparatus for a large ozone contact tank 1 corresponding to the actual scale, and obtained the following new findings.

That is, (1) The water flow around the rising bubble flow above the ozone diffuser 4 becomes a counterclockwise circulation mixed flow 9 in FIG.

However, (2) a high-speed water stream 10 is formed at a portion from the ozone diffuser 4 to the bottom of the contact tank 1a where there is no bubble stream.
It was found that a similar high-speed water stream 10 was also formed in the space between the ozone diffuser 4 and the side wall 11 and between the ozone diffusers 4. This high-speed water stream 1
When 0, the gas-liquid contact flows out as treated water with sufficient contact, so that a loss occurs in performing sufficient gas-liquid contact.

By the way, during operation, it is necessary to inspect and replace the diffuser cylinder 3 of the ozone diffuser 4 for clogging and leaks. A distance (space) of about 0.8 m is secured between the ozone diffuser 4 and the side wall 11 and between the ozone diffusers 4 so that a person can pass through the ozone diffuser 4.
Is located above the bottom surface of the contact tank 1a, there is a problem that the scattering cylinder 3 becomes a protrusion and inspection and maintenance work is not easy. Further, when a space is reserved for maintenance and inspection, a portion of the mixed flow 9 due to the rising bubble flow is deviated from the main flow, which is also a factor for forming the high-speed water flow 10.

The present invention has been made in view of the above points, and it is an object of the present invention to provide an ozone contact tank capable of improving processing performance and easily performing maintenance and inspection. .

[0011]

According to the first aspect of the present invention,
A contact tank into which the water to be treated flows, and an ozone diffuser arranged in the contact tank and comprising a header pipe and a diffusion cylinder are provided, and the ozone diffuser is provided on the bottom surface of the contact tank and with this bottom surface. It is an ozone contact tank characterized by being arranged without forming a flow path therebetween.

According to the second aspect of the present invention, there is provided a contact tank into which the water to be treated flows, and an ozone diffusing device arranged in the contact tank and comprising a header pipe and a diffusion cylinder. And an ozone diffusing device is housed in the housing recess, and the housing recess is covered with a cover member.

According to a third aspect of the present invention, on both side walls of the side wall of the contact tank, which are arranged parallel to the inflow direction of the water to be treated,
3. The ozone contact tank according to claim 1, further comprising a baffle wall protruding inward.

According to a fourth aspect of the present invention, there is provided a contact tank into which the water to be treated flows, and an ozone diffuser arranged in the contact tank, the ozone diffuser including a header pipe and a diffuser cylinder. It is an ozone contact tank characterized by covering the above with a cover member.

[0015]

According to the invention described in claim 1, a circulating mixed flow is generated in the water to be treated by the rising bubble flow of the ozonized gas generated from the ozone diffuser, and the water to be treated is ozonized in the circulating mixed flow. Treated with gas to produce treated water. Since the ozone diffuser is placed on the bottom surface without forming a flow path between it and the bottom surface, the range of the circulation mixed flow is expanded to the vicinity of the bottom surface, and the effective water depth of the contact tank is also increased. The gas-liquid contact performance with the ozonized gas is improved.

According to the second aspect of the invention, a circulating mixed flow is generated in the water to be treated by the rising bubble liquid of the ozonized gas generated from the ozone diffuser, and the water to be treated is ozonized in the circulating mixed flow. Treated with gas to produce treated water. Since the ozone diffuser is housed in the concave portion on the bottom surface, the range of the circulating mixed flow can be further expanded to the vicinity of the bottom surface. Further, since the ozone diffuser is covered by the cover member, the worker can pass over the cover member,
It is not necessary to extend the space between ozone diffusers.

According to the third aspect of the present invention, since the baffle walls are provided on both side walls of the contact tank, it is possible to eliminate the high-speed flow in the vicinity of both side walls of the water to be treated, and further improve the gas-liquid contact performance. Can be made.

According to the fourth aspect of the invention, since the ozone diffuser is covered by the cover member, the worker can pass over the cover member, and there is no need to expand the space between the ozone diffusers. Absent.

[0019]

Embodiments of the present invention will now be described with reference to the drawings. 1 and 2 are views showing a first embodiment of an ozone contact tank according to the present invention.

1 and 2, the ozone contact tank 1
Is provided with a contact tank 1a for treating treated water to be treated water, and an ozone diffuser 4 including a header pipe 2 and a dispersing cylinder 3 arranged in the contact tank 1a. Of these, contact tank 1a
Is an upper inflow weir 7 through which the water to be treated flows in from its upper end,
The partition wall 8 from which the treated water flows out, and the side walls 11 and 11 located on both sides and parallel to the inflow direction of the treated water.
And have.

The ozone diffuser 4 is disposed on the bottom surface 21 of the contact tank 1a without forming a flow path between the ozone diffuser 4 and the bottom surface 21. It is fixed at 21.

The fitting 22 is made of stainless steel so that the header tube 2 of the ozone diffuser 4 and the bottom surface 21 are supported and fixed (directly mounted) at the shortest distance possible. The fixture 22 may be made of another ozone resistant material such as ceramics.

A cover member 23 is laid so as to cover the ozone diffuser 4. The cover member 23 is composed of a lattice-shaped framework, and the vicinity of the upper surface of the dispersion cylinder 3 is located within the lattice gap of the lattice-shaped framework. The cover member 23 may be made of a net-like or porous material and installed on the bottom surface 21. The cover member 23 is strong enough for a person to walk and is made of an ozone resistant material such as stainless steel or ceramics.

Further, as shown in FIG. 2, both side walls 11, 1
1, one or more baffle walls 41 projecting inward are provided in a protruding manner. Unlike the side walls 11 and 11, it is not necessary to consider the water pressure resistance of the baffle wall 41. Therefore, the baffle wall 41 is arranged upward from the bottom surface 21 along the side wall 11 using a stainless angle or a stainless plate. When the replacement is performed within about one year, a plastic plate such as vinyl chloride may be used as the baffle wall 41.

Next, the operation of this embodiment having such a configuration will be described.

As shown in FIGS. 1 and 2, the water to be treated which has flowed into the contact tank 1a from the upper end of the upper inflow weir 7 flows to the partition wall 8 side. During this time, the ozonized gas flows into the contact tank 1a through the header pipe 2 and the scattering cylinder 3, and the upward bubble flow of the ozonized gas forms a counterclockwise circulation mixed flow 9 (FIG. 1) in the contact tank 1a. To be done. Then, in the circulating mixed flow 9, the rising bubble flow of the ozonized gas and the water to be treated come into gas-liquid contact,
Oxidized substances such as 2-methylisoborneol (2-MIB), which is an odor component in the water to be treated, are oxidized and decomposed. The treated water after the treatment flows out from the lower part of the partition wall 8.

By the way, in FIG. 1, the ozone diffuser 4 is shown.
Is directly attached to the bottom surface 21, so the position where the rising bubbly flow of the ozonized gas from the scattering cylinder 3 is near the bottom surface 21 unlike the conventional device. Therefore, the range of the circulating mixed flow 9 in the contact tank 1a formed by the rising bubble flow of the ozonized gas is expanded to the vicinity of the bottom surface 21. As a result, unlike the conventional apparatus, the high-speed water stream 10 that does not contribute to the gas-liquid contact generated below the ozone diffuser 4 is eliminated, and only the treated water that is sufficiently gas-liquid contacted by the circulating mixed stream 9 is eliminated. Will be obtained.

Further, the water depth of the contact tank 1a affects the reactivity such as the ozone absorption rate, and the greater the water depth (usually about 5 m), the higher the reactivity. In the conventional device, ozone diffuser 4
The lower part of the ozone diffuser 4 has an ineffective water depth, but in the present invention, the lower part of the ozone diffuser 4 can be utilized as an effective water depth. Further, in the present invention, since the ozone diffusing device 4 is located near the bottom surface 21, it is easier to secure a scaffold for inspection and maintenance even if the projection shape of the diffuser cylinder 3 is the same as the conventional one.

Further, since the cover member 23 is provided, a scaffold with few steps can be formed mainly by the skeleton of the cover member 23, and thus the protrusion of the scattering cylinder 3 can be lowered from the scaffold position, so that inspection and maintenance can be performed. You can do it more safely. Further, since the spread of the rising bubbly flow of the ozonized gas generated from the dispersion cylinder 3 is small in the immediate vicinity of the dispersion cylinder 3, the dispersion cylinder 3 is provided with a slight margin in diameter (about 75 mm) and length (about 500 mm). The gas-liquid contact performance is not adversely affected even if the cover member 23 made of the lattice framework or the net-like material is provided.

As described above, the cover member 23 secures a highly safe scaffold for inspection and maintenance without adversely affecting the gas-liquid contact performance, so that the operator can pass over the cover member 23. . Therefore, it is possible to eliminate the wasteful space for inspection and maintenance which is provided between the ozone diffuser 4 and the side wall 11 and between the ozone diffusers 4 in the conventional device. Therefore, the diffuser cylinder 3 of the ozone diffuser 4 can be appropriately arranged without an empty space, and the high-speed water flow 10 that has been conventionally generated can be reduced. When the ozone diffuser 4 is thus covered with the cover member 23, the space for inspection and maintenance provided between the ozone diffuser 4 and the side wall 11 and between the ozone diffusers 4 must be removed. Therefore, in this case, the ozone diffusing device 4 may be arranged so as to form a space between the ozone diffusing device 4 and the bottom surface 21 as in the conventional device.

On the other hand, when a large inspection / maintenance space is provided on both side walls 11, 11 like the ozone contact tank 1 of the conventional apparatus, this space becomes the main route of the high-speed water stream 10 and becomes a major factor of performance deterioration. . However, according to the present invention, the provision of the baffle wall 41 reduces the formation of the high-speed water flow 10 in the vicinity of the both side walls 11, 11 and improves the air flow contact performance. Baffle wall 41
The number and shape of laying of No. 1 vary depending on the form of the ozone contact tank 1, but since the production is easy, several types can be produced to be the best one. Also, this baffle wall 41
Since has a simple structure with a small space, it is possible to maintain the same inspection and maintainability as before.

Next, a second embodiment of the ozone contact tank according to the present invention will be described with reference to FIG. In this embodiment, the contact tank 1
A bottom surface 21 of a is provided with a concave portion 32 for accommodating the ozone diffusing device 4, and the rest is substantially the same as that of the first embodiment shown in FIGS. 1 and 2.

In this embodiment, the same parts as those in the first embodiment shown in FIGS. 1 and 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

As shown in FIG. 2, the bottom surface 21 of the contact tank 1a
A concave portion 32 is formed in the concave portion 32, and the ozone diffuser 4 is housed in the concave portion 32. Further, the concave portion 32 in which the ozone diffusing device 4 is housed and arranged is covered by the cover member 23. A discharge passage 35 is communicated with the recess 32, and the ozone diffuser 4 is supported and fixed in the recess 32 by a fixture 22.

Next, the operation of the second embodiment will be described.
The rising bubbles of the ozonized gas generated from the diffuser cylinder 3 of the ozone diffuser 4 are generally generated from the outer surface above the center of the diameter of the diffuser cylinder 3, and no bubble is generated from the lower part.
For this reason, the space below the center of the diameter of the dispersion cylinder 3 and below is present as a portion where there is no gas-liquid contact. In the present embodiment, since the concave portion 32 is provided on the bottom surface 21 and the ozone diffuser 4 is arranged inside the concave portion 32, the portion having no gas-liquid contact can be eliminated, and the gas-liquid contact performance can be improved. it can.

The upper surface of the dispersion cylinder 3 is covered with a cover member 23, which is the safest form for inspection and maintenance.
If the scaffolding for inspection and maintenance is sufficient, the upper part of the center of the diameter of the scattering cylinder 3 may be projected above the bottom surface 21.

As described above, according to the present embodiment, the circulating mixed flow 9 of water is formed up to the vicinity of the bottom surface 21 of the ozone contact tank 1, and the treated water which is sufficiently gas-liquid contacted is obtained. Since the effective water depth of the contact tank 1a is increased, the gas-liquid contact performance is improved. Further, the scaffolding can be secured by the cover member 23, which enables safer inspection and maintenance work. Since the scaffolding is secured by the cover member 23 in this way, it is not necessary to provide an empty space for securing the scaffolding between the ozone diffusers 4. Therefore, it is possible to effectively prevent the generation of the high-speed water flow caused by the empty space.

It should be noted that the cover member 23 provided in the first and second embodiments is separable, and the dispersed cylinder 3 to be inspected and maintained.
A cover member 2 that can be divided for each (may be plural)
3 may be removed so that work can be performed. Although the cover member 23 may be covered on the upper part of the dispersion cylinder 3,
When the scaffolding based on the frame member of the cover member 23 can be sufficiently made, such as when the space between the two is wide, the height of the cover member 23 may be lowered to near the height of the diameter center of the dispersion cylinder 3.
As a result, the level difference between the cover member 23 (scaffolding) and the bottom surface 21 is further reduced, and the safety is improved, and the inspection and maintenance of the dispersed cylinders 3 are facilitated.

[0039]

According to the invention of claim 1, in the water to be treated, the range of the circulating mixed flow can be expanded to the vicinity of the bottom surface of the contact tank, and the effective water depth of the contact tank can be increased. The gas-liquid contact performance between water and ozonized gas can be improved. Therefore, the treatment performance of the water to be treated can be improved.

According to the second aspect of the invention, in the water to be treated, the range of the circulating mixed flow can be further expanded to the vicinity of the bottom surface of the contact tank. Also, by covering the recess with a perforated plate, it is possible to easily pass through the cover member for maintenance and inspection. Further, since it is not necessary to expand the space between the ozone diffusers, it is possible to reduce the high-speed water flow between the ozone diffusers.

According to the third aspect of the present invention, the high-speed water flow in the vicinity of both side walls can be eliminated, and the gas-liquid contact performance can be further improved.

According to the fourth aspect of the present invention, since it is not necessary to expand the space between the ozone diffusers, it is possible to reduce the high-speed water flow between the ozone diffusers.

[Brief description of drawings]

FIG. 1 is a side sectional view showing a first embodiment of an ozone contact tank according to the present invention.

FIG. 2 is a plan view showing a first embodiment of the ozone contact tank according to the present invention.

FIG. 3 is a side sectional view showing a second embodiment of the ozone contact tank according to the present invention.

FIG. 4 is a view showing a conventional ozone contact tank.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Ozone contact tank 1a Contact tank 2 Header pipe 3 Cylinder 4 Ozone diffuser 9 Circulating mixed flow 11 Side wall 21 Bottom 22 Fixture 23 Cover member 41 Blocking wall

Claims (4)

[Claims] 1. A contact tank into which water to be treated flows, and an ozone diffuser arranged in the contact tank and comprising a header pipe and a diffusion cylinder, the ozone diffuser being provided on the bottom surface of the contact tank. The ozone contact tank is characterized in that it is arranged without forming a flow path between the ozone contact tank and the bottom surface. 2. A contact tank into which water to be treated flows, and an ozone diffuser arranged in the contact tank, the ozone diffuser including a header pipe and a diffusion cylinder, and a storage recess on the bottom surface of the contact tank. As it forms
An ozone contact tank, wherein the ozone diffusing device is housed and arranged in the housing recess, and the housing recess is covered by a cover member. 3. A blocking wall protruding inward is provided on both side walls of the side wall of the contact tank which are arranged parallel to the inflow direction of the water to be treated. The ozone contact tank according to any one of the above. 4. A contact tank into which water to be treated flows, and an ozone diffuser arranged in the contact tank and comprising a header pipe and a diffusion cylinder, the ozone diffuser being covered with a cover member. An ozone contact tank characterized in that